Hi, I'm a Ham Radio operator, Computer tech, and I'm here to learn.

[Sunking]

I love YouTube The guy made some good points, but his controller cost him way more than the one I bought. In any case, he showed a few good points about what has to be inside the controller for the DC to DC to happen, and he showed how he tested it on his 200 watt, 24 volt panel to see MPPT in action. Was he wrong? I will have that controller this week, it is in the states already. I figure it will be here Wednesday, so the first thing to do is take it apart. If it does not pass the visual, there won't be any need to test it, it will be a fraud, and I will get a full refund, and try again.

YOu do not have to take it apart. Just hook it up and look at the input and output currents and voltages. If the output current is equal or less than input it is a fraud.

With a PWM the input voltage assuming the battery is demanding a charge will be about 1 volt higher than the battery voltage. Input Current = Output Current. So that 100 watt panel will input about 60 to 65 watts into a battery.

If it is MPPT on the input you will see roughly 18 volts @ 5.5 amps, and on the output 12 volts @ 8.1 amps. The output current will be significantly higher then the input current.

[SOLAR_FL]

Sure is. With PWM controllers Input Current = Output Current. So with say a standard 100 watt battery panel with an Imp = 5.55 amps. You will see 5.5 amps going into the controller and see 5.5 amps going out to the battery. Net effect it turns your 100 watt panel into a 66 watt panel 12 volts x 5.5 amps = 66 watts.

With true MPPT Output Current = Panel Wattage / Battery Voltage - 2 to 3 % conversion loss. So that same 100 watt panel outputs 8.1 amps or 97 watts. Huge difference.

Quit watching You Tube. Stick with facts.

I love YouTube The guy made some good points, but his controller cost him way more than the one I bought. In any case, he showed a few good points about what has to be inside the controller for the DC to DC to happen, and he showed how he tested it on his 200 watt, 24 volt panel to see MPPT in action. Was he wrong? I will have that controller this week, it is in the states already. I figure it will be here Wednesday, so the first thing to do is take it apart. If it does not pass the visual, there won't be any need to test it, it will be a fraud, and I will get a full refund, and try again.

[Sunking]

is there a way to test it and know that its MPPT feature is actually working?

Sure is. With PWM controllers Input Current = Output Current. So with say a standard 100 watt battery panel with an Imp = 5.55 amps. You will see 5.5 amps going into the controller and see 5.5 amps going out to the battery. Net effect it turns your 100 watt panel into a 66 watt panel 12 volts x 5.5 amps = 66 watts.

With true MPPT Output Current = Panel Wattage / Battery Voltage - 2 to 3 % conversion loss. So that same 100 watt panel outputs 8.1 amps or 97 watts. Huge difference.

Quit watching You Tube. Stick with facts.

[SOLAR_FL]

Looks like you are on your road to discovery!

Put it this way - would you rather have a Wouxon or Boefeng radio, or an Icom/Yaesu/Kenwood, or move up to a Motorola / Harris / GE etc? Price-point is one thing, but durability, specs, and support is another.

Take the reviews with a grain of salt. When additional details are given, many are doing it wrong, but don't have the knowledge that they are, so the reviews are great! They just replace expensive batteries much sooner than usual but don't know why. For example, Wouxon radios may seem like a great bargain, but they have awful image-rejection! Out in the boonies one won't detect this problem, but as soon as you move into an rf-congested area, the image-rejection becomes a big problem. Yet people like them mostly for their low price point and don't realize that what the radio is getting hammered with comes about 40mhz above the display frequency.

If you only eat beef-jerky, you'll never know what a superb steak is all about, and give the jerky rave reviews.

Bravo, all very good points. I own an Icom 756 pro II that I love, a Yeasu mobile I love, and a Wouxon HT. I don't know if we can put these complicated radios in the same class as a simple controller, yet your point is taken. As I said, I will test the controller in any way I can to judge its quality. It is all I can do since I bought it already, and I'd like to know that I can trust my judgment for future project parts.

In defense of small HT's everywhere, small is what a lot of Hams want, and small is not how you design a radio with great image rejection. So many small HT's have very poor image rejection, and 100's of features that nobody really needs, and most don't use. That's why one of the best HT's to have is a repurposed Motorola business band radio. No frills, but it really works well.

I will look on Youtube for anyone who has that controller I bought and reviewed it. I often find that sort of thing there. I decided to try to get a couple of golf cart batteries for my first solar system, and I based that on cost, and a great youtube video from a guy who is off the grid with solar and wind generation. He showed his system in his youtube video, and his garage looked like the control room at a power plant, but I guess that is what it really is.

Update:

I found this review that is awesome, please look at it and tell me what you think of how the guy tested his China made MPPt controller? I will do the same.

https://www.youtube.com/watch?v=6q2ICp7acvA

[PNjunction]

Looks like you are on your road to discovery!

Put it this way - would you rather have a Wouxon or Boefeng radio, or an Icom/Yaesu/Kenwood, or move up to a Motorola / Harris / GE etc? Price-point is one thing, but durability, specs, and support is another.

Take the reviews with a grain of salt. When additional details are given, many are doing it wrong, but don't have the knowledge that they are, so the reviews are great! They just replace expensive batteries much sooner than usual but don't know why. For example, Wouxon radios may seem like a great bargain, but they have awful image-rejection! Out in the boonies one won't detect this problem, but as soon as you move into an rf-congested area, the image-rejection becomes a big problem. Yet people like them mostly for their low price point and don't realize that what the radio is getting hammered with comes about 40mhz above the display frequency.

If you only eat beef-jerky, you'll never know what a superb steak is all about, and give the jerky rave reviews.

[SOLAR_FL]

That is a 28 ah battery and you could do better with a hybrid marine battery
Battery is a bit small for your use and not sure it could take the charge current of two of those panels. Which would be close to a c/2 charge rate

The charge controller claims to be mppt but at that price probably a rebadged PWM. You get what you pay for.

So the charge controller is water under the bridge, I already paid for it, and it is on its way to me. So I know that people like to claim that any bargain is really somebody getting ripped off, but with that said, is there a way to test it and know that its MPPT feature is actually working? The seller has sold a lot of them, and nobody came back and claimed that it was a fraud. I buy from China all the time, and rebranding is truly just that, not a bad product, but a product with some other name on it. 99% of electronics are made outside the USA. That is starting to change, but change is slow. I hope we bring most of the manufacturing jobs back to the USA, and even Canada, or maybe even Mexico. In a round about way, helping our neighbors helps us at the same time.
My O'scope was made in China, and two or three major well respected electronics companies sell the same model, button for button, and feature for feature, but it will say B&K, or Techtronics on it, and cost another $1000.00+ on top of what I paid.

The Ebay seller sells lower end MPPT controllers with no LCD display, and the Morningstar will supply a display, but only as an optional part. I will be happy to test the controller, feature for feature, and report back on its operation.

I am currently shopping for other batteries. Even though the UPS batteries may sit and do almost nothing, that will be better than destroying them because of me not following competent information from you guys.
I like the one big battery, but I'm not ready to pop $7 or $800.00 down to get one. The other suggestion was golf cart batteries, and after researching them, they may be the starting point for me.

Joe

[Sunking]

If I wanted to use both panels, could I get them both to work with a single 2000a AGM? The controller is here
http://www.ebay.com/itm/281114918367...84.m1439.l2649

Joe as all things you get what you pay for. With 200 watts of panel power I suggest you look at another controller of known quality like a Morningstar Sun Saver MPPT controller. It will run circles around the unit you are looking at

The AGM I would plan to buy is this >

http://www.ebay.com/itm/XS-Power-Deep-Cycle-12-Volt-12V-AGM-Power-Cell-Battery-D925-Brand-New-2000-amps-/310642681324?pt=Motors_Car_Truck_Parts_Accessories&hash=item4853bf25ec&vxp=mtr

Maybe there is a better deal on a better suit battery for the two panels?

No Joe it is no better than what you have now. That battery is really a Starting Battery in hiding. The dead give away is it list CCA or Cold Cranking Amps. No deep cycle battery has a CCA or MCA spec as they are not capable of doing that. Besides it is a 28 AH battery. You have 24 AH now. Minimum you need is 150 AH up to 250 AH.

My question to you is why are you stuck on AGM?

AGM are good batteries but not the best fit always. They have niche applications like portability, extreme cold climates, unusual installation orientation like on their side, and high current applications. The trade-off with AGM they cost about twice as much as Flooded and only last half as long as Flooded. So if you go with AGM you need to understand what you are giving up like money and battery life.

So my questions are these:

1) is my current panel performing well at 7.4 amps short circuit current at noon?

2) Will two panels work well with one single 2000 amp AGM, and the controller I identified above?

3) What kind of load could I put on the system once it is all installed and working to charge the 200 amp AGM?

4) If it is an inverter, what size, and do I care if it is true sine, or modified sine?

A1. Without seeing the specs for a 100 watt battery panel sounds good. What is the Isc spec say?. Forget trying to test Vmp and Imp as it is not really possible except with a true MPPT controller on a discharge battery. MPP is a moving target of resistance. For a 100 watt battery panel a dynamic resistances of 2.8 to 20 Ohms.

A2. No such thing as a 2000 amp AGM. Batteries are rated in Amp Hours. Th ebattery you are looking at is 28 Amp Hours. The 2000 amp is pure nonsense.

A3. Again you need to understand battery specs. Batteries are rated in AMP HOURS, not amps. For a 12 volt system with a MPPT controller here is your rule of thumb.

1 Watt of Panel to to Amp Hour of Battery to 1 watt of a load device. In your case 200 watts of pane, 200 Amp Hours of Battery, with a 200 watt maximum load. Pretty easy to figure out. For MPPT current is even easier. Panel Wattage / Battery Voltage. So 200 watts / 13 volts = 15 amps. A 15 amp charger can support a 120 to 200 AH battery.

So please get off this 20 to 30 AH battery stuff.

A4. Inverter size depends on battery type being either AGM/Hybrid or Flooded, and the battery size in Amp Hours. For AHM you can load them up to about C/4 where C = the battery Amp Hour rating. So if you have a 100 AH AGM battery, it can supply up to 25 amps without excessive voltage sag. So an inverter of roughly 12 volts x 25 amps = 300 watts. For a Flooded Lead Acid Battery max current drain is C/8. A 12 volt 200 AH FLA can support a 300 watt load..

Here is my last tip for you. there is a class of Flooded Lead Acid Batteries called Hybrid batteries. They come in marketing names like RV, Marine Deep Cycle, Golf Cart, and Floor Machines. This is what a ham operator is looking for. A hybrid battery is a Cross between a SLI (Starting Lighting Ignition aka cranking battery) and a Deep Cycle Battery. It is a trade-off. To get the high current discharge you give up some cycle life. A hybrid can easily deliver up to C/2 discharge current. You want something in the 200 AH range. So here is a good shopping list of batteries to look at.

Trojan T-105. 6 volt 225 AH Golf Cart Batteries. They can deliver 100 amps no problem.
US Battery US2200 6 volt 220 AH Golf Cart Batteries that can deliver 75 amps no problem

[Naptown]

That is a 28 ah battery and you could do better with a hybrid marine battery
Battery is a bit small for your use and not sure it could take the charge current of two of those panels. Which would be close to a c/2 charge rate

The charge controller claims to be mppt but at that price probably a rebadged PWM. You get what you pay for.

[SOLAR_FL]

I knew I came to the right forum, you guys have already educated me in a big way.

So here is what's new, and what I propose based on input.

The panel I have in 12 pm/ noon sun in mid/south Florida gave me short circuit current of 7.4 amps. No load voltage was 20 to 22 volts. Short circuit testing does not allow me to get voltage under load, but I may try loading it after I complete this message.

-----------
Update: I used a PC fan that requires 12v @ 1.5 a, and it ran supper fast at 16 volts @ 1.4 amps draw. This is with partial sun, as it got cloudy in the middle of my testing. I am guessing that the charger regulator will regulate the voltage and current to the proper level for charging batteries.
-------------
If I wanted to use both panels, could I get them both to work with a single 2000a AGM? The controller is here

http://www.ebay.com/itm/281114918367?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I only had feedback to judge the quality of the charger, and it was mostly all very good. Maybe one of you knows this product, an can share a personal experience you have had with it?

About the current batteries:
They are new, and bought to replace UPS batteries, but not used because the UPS truly failed and I replaced it.

The AGM I would plan to buy is this >

http://www.ebay.com/itm/XS-Power-Deep-Cycle-12-Volt-12V-AGM-Power-Cell-Battery-D925-Brand-New-2000-amps-/310642681324?pt=Motors_Car_Truck_Parts_Accessories&hash=item4853bf25ec&vxp=mtr

Maybe there is a better deal on a better suit battery for the two panels?

So my questions are these:

1) is my current panel performing well at 7.4 amps short circuit current at noon?

2) Will two panels work well with one single 2000 amp AGM, and the controller I identified above?

3) What kind of load could I put on the system once it is all installed and working to charge the 200 amp AGM?

4) If it is an inverter, what size, and do I care if it is true sine, or modified sine?

I may use it to power a TV, or operate ham radio. I currently have no plan to go past two panels.

Lastly, I have a few Crimpmaster crimpers, and any new die I found to do MC4 cost much more than buying the tool off ebay. Does anyone sell a MC4die that will fit it for a reasonable cost?

I will take the advice and buy a 100 ft 10 gauge cable with MC4 on both ends, but I have two type H connectors coming, and one will need to be used to put both panels in parallel mode. So I think I may need to crimp at least one connection myself. I will appreciate the experience too, as I always like to learn new things.

TNX Joe

[Sunking]

I have one Renogy 100 watt panel, and a second on order.
I will set the whole thing up on a small set of 3 X 8Amp UPS batteries.

You are really asking for trouble here Joe. For one UPS batteries are not made for cycle application, they are made for emergency standby power, and if forced into cycle service will only give you 50 to 150 cycles. Secondly parallel batteries are a poor idea and should not be used unless it is necessary, and unless you need more than 4000 AH it is never necessary.

Last point is with a 200 watt panel and MPPT controller your charger current will be up around 17 amps which is way too much for a 24 AH battery. Smallest you want to go is C/8 or in your case about 140 AH is as small as you want. You stated you are a ham radio operator, so am I and on my setup I have a 240 watt panel, 80 amp MPPT controller, and a brand new Concorde 12 volt 250 AH battery which is a perfect fit and size for the panel. Assuming good Sun everyday I can operate my IC-9100 24 x 7 so long as I do not rag chew all the time in FM mode. So ditch those batteries and get you something useful like a pair of Trojan T-105's. That will allow you to do something useful.

73's to you.

[PNjunction]

I have one Renogy 100 watt panel, and a second on order. I bought a charge controller from China, on Ebay that supports MPPT, and has a nice LCD display to show various parameters of the system.

Ok, so you plan to put them in series (assuming they are the off-grid 18-20v ocv type) to power an mppt controller. If so, make sure that the controller is *truly* mppt voltage-power point tracking, and not just a simpler one with merely an mppt silkscreen label. Caveat emptor!

I will set the whole thing up on a small set of 3 X 8Amp UPS batteries.

Are these relatively new, or just pulled out of some random ups after a few years of use? If the latter, I would just recycle them and start on the right footing with a fresh battery.

It is critical to find out if these are GEL or AGM batteries. There is an important difference in both voltage and current when recharging them. If GEL, just recycle them as they are not really applicable to general purpose solar use - mainly because you need to charge them SLOWLY as compared to a flooded or agm. Since solar-insolation time isn't a luxury for most of us, gel's are out of the running.

Speaking of solar-insolation, where are you located? Roughly will do. Solar-insolation hours are a critical part of planning out a system, as these hours are very different from sunrise-to-sunset hours. You may only have 30 minutes of usable "solar" insolation in the winter, even though the day is lit from 8a to 4pm for walking around. Basically, the panels take an early morning and late evening snooze. Many look up and use the PVWATTS or PVWATTS 2 program online.

Are these paralelled to accomplish a 24ah battery? If so, and even if they are agm's which can take up to about .3C inrush current, they won't like the total output of your two panels. In fact, using only ONE of your panels to a pwm-controller would do fine - assuming those existing batteries aren't just toasted already.

[Mike90250]

...I will set the whole thing up on a small set of 3 X 8Amp UPS batteries....

Welcome Joe.

200w of panel is a bit much for 24ah of battery. And most of the UPS batteries are gel cells, which don't do well in deep cycle usage, 12V 200ah is a better size of battery for 200w of pv. (2, 6v golf cart batteries in series is a good starter set)

[Naptown]

For one or two cables just go to a retailer (our host solar town comes to mind ) and buy a made up cable twice the length you need one way and cut in half
Crimping your own connectors for one or two cables becomes cost prohibitive. The crimp tool I have was over $300.00
Granted this is a pro tool and they can be had for less it is still cheaper to nuy pre made cables.

[SOLAR_FL]

I have one Renogy 100 watt panel, and a second on order. I bought a charge controller from China, on Ebay that supports MPPT, and has a nice LCD display to show various parameters of the system.
I will set the whole thing up on a small set of 3 X 8Amp UPS batteries. I am a long way from having it all in one place, and even further from having the tools, and extra wire to set it all in operation.
I tested the one panel in late afternoon and with a small 12vdc fan that required .250 ma on it, it held its voltage at 20v, and drew .282 ma. I may get a full sun short circuit reading on Saturday.
Renogy makes a nice panel, I like the construction and quality of all parts used. I paid $140 for each panel with free shipping. I don't know if I could have done better elsewhere.

I would like to get a good lead on low cost wire to use with my MC4 connectors, and to hook the system up. Any feedback on this is welcomed.

I am in Jensen Beach, Florida.

I also work for a power company, and we have some customers who have Solar systems who sell power back to us. On some days they use all they get, but they close on weekends, and the system keeps going through holidays. So in the end, they do pretty well.

Joe